Differential Interference Contrast (DIC)

Differential Interference Contrast (DIC) is a contrast-enhancing technique that utilizes polarized light in conjunction with special optical beam splitters known as Wollaston or Nomarski prisms to create 3-Dimensional, shadow-like images on many types of stained or unstained samples. DIC images can range from gray in appearance to very colorful depending on the sample, the orientation of the polarizing filters and the use of other features, such as compensation plates. Differential interference contrast microscope is similar to phase contrast in that it is very useful for viewing samples that are difficult to image under regular brightfield illumination, but DIC has a few advantages over phase contrast that make it desirable. For example, the halos often encountered using phase contrast are not present using DIC. Secondly, DIC is able to utilize the full numerical aperture of the objective, which results in better resolution and clearer detail than phase contrast images. Also, DIC can yield beautifully colorful images for photomicrography purposes. DIC can be found on both upright and inverted microscopes, can be used with transmitted or reflected illumination, and is just as useful with metallurgical samples as it is with biological samples. However, DIC is an expensive contrast technique and it usually only available on microscopes used in research.